A new study almost 20 years in the making provides some of the strongest evidence yet of the 'speciation reversal' phenomenon -- where two distinct lineages hybridize and eventually merge into one -- in two lineages of common ravens.

Dr. Kevin Omland, professor of biological sciences at University of Maryland, Baltimore County (UMBC) initially began work on this project in 1999, Common Ravens were considered a single species worldwide. He thought further research might uncover two distinct species -- perhaps an "Old World" and "New World" raven -- but the real story is much more complicated. Omland reported the existence of two Common Raven lineages in 2000, one concentrated in the southwestern United States dubbed "California," and another found everywhere else (including Maine, Alaska, Norway and Russia) called "Holarctic."

Since then, the plot has thickened. Two undergraduates in Omland's lab, Jin Kim and Hayley Richardson, former URA's, analyzed mitochondrial DNA from throughout the western United States and found the two lineages are extensively intermixed.

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